Atrial fibrillation (AF) is a large public health problem that affects about 1% of the population in the United States. It confers an increased risk for stroke and thromboembolism, but the stroke risk is not equal in all patients. Further refinement in stratifying stroke risk in patients with AF will help in properly directing therapy for AF patients while minimizing adverse events. Warfarin is the first-line treatment for stroke reduction in patients with AF, but many new drugs are on the horizon that will significantly change practice. New and improved cardiac monitoring techniques and devices will help with detection of AF in those at risk for stroke and will assist in assessing which patients will most benefit from anticoagulation.